RUI: Experimental and Theoretical Investigation of Threshold Energy Barriers and Substituent Effects for the 1,2-Halogen Interchange Reaction in Haloalkanes

北卡罗来纳大学阿什维尔分校的伯特·霍姆斯和乔治·希尔德在实验物理化学计划的支持下，对化学活化的氢卤烷的单分子反应动力学进行了合作实验和理论研究。这项研究建立在PI之前对一种不寻常的气相机制的调查基础上，这种机制涉及相邻碳上的卤素交换。该计划以氢卤代烃为重点，确定各种1，2-卤素交换反应和1，2-HX(式中X=F、Cl或Br.)消除反应的阈值势垒和取代基对这些势垒的影响。电子结构计算将给出反应物和过渡态的频率和惯性矩，这些将与RRKM理论一起用于计算速率常数，并允许分析结构-反应性关系的趋势。该项目的研究成果可以提高对涉及氢氯氟烃的燃烧、焚烧和大气化学过程的理解。这项研究预计将提供充分的机会，通过让学生参与旨在发展分析思维能力和解决问题能力的研究，并鼓励对化学科学高级工作的兴趣，来加强本科教育。

Bert Holmes and George Heard of the University of North Carolina at Asheville are supported by the Experimental Physical Chemistry Program to carry out a collaborative experimental and theoretical study of the kinetics of unimolecular reactions of chemically activated hydrohaloalkanes. The research builds on the PIs' previous investigations of an unusual gas phase mechanism involving the exchange of halogens on adjacent carbons. Focusing on hydrohaloalkanes, the plan is to determine threshold energy barriers and the effect of substituents on these energy barriers for various 1,2 halogen interchange reactions and for the 1,2-HX (where X = F, Cl, or Br) elimination reaction. Electronic structure calculations will give the frequencies and moments of inertia of the reactant and transition state, and these will be used with RRKM theory to calculate rate constants and permit the analysis of trends in the structure-reactivity relationships. Research outcomes from this project could improve the understanding combustion, incineration, and atmospheric chemical processes involving hydrochlorofluorocarbons. This research is expected to provide ample opportunities to enhance undergraduate education by involving students in research that is designed to develop analytical thinking skills and problem-solving ability, and encourage interest in pursuing advanced work in the chemical sciences.